Process for producing printing-plates.



'NTTED TATES PATENT @FFTGE.

EMANUEL SPTTZER, 0F

MUNICH, GERIVIANY, ASSIGNOR OF TWO-FOURTHS T O IVIRS. ALPHA O.GDLDSMITH, OF BERLIN, GERMi iNY, AND ONE-FOURTH TO SOPHIE 'SPITZER,OFMUNICH, GERMANY.

\ PRQGESS FQF? PRODUGENG Pl lNTlNGwPLATES.

$pecification of Letters Patent.

latented Feb. 26, i907.

Application filed July 7, 1902. Serial No. 114,682. (Specimenal To allwhen it may concern: I

Be it known that I, EMANUEn Srrrznn, kunstmaler, a citizen of the Empirec Austria, residing at Munich, Bavaria, Germany,

have invented certain new and useful Improvements in Processes forProducing Printing-Plates; and I do hereby declare the following to be afull, clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame. 7

My invention relates to the art of making printing-plates, and inparticular to the manufacture of photomechanical printing plates orsurfaces;

The object of this invention is to produce printing-plates byphotomechanical methods directly from continuous photographic plates orfilms produced by light, X, 'or Becquerel or other rays-that is, withoutthe use of' screens or otherartifi'cial stippling steps.

The characteristic feature of the invention eonsists in the fact that aphotographic plate is directly that is, without the use of screens orother artificial-stippling steps copied onto the plate to be etchedprovided with a sensitive layer, the copy then subjected to theinfluence of an etching agent and the etching allowed to take place, theresult being an etched plate with minute cavities and between themminute elevations or stipples massed so as to correspond to thedifferent shade and light values of the original and representing thesame in all its finest details in a most erfect manner.

The fol owing example illustrates what I consider a preferable manner ofcarrying out my invention. 1 coat a polished printinglz. in the mannerwell known with a coatmg of sensitive solution, such as chrome-glue orgelatin solution, as used in the art. it is important to dry thiscoating as uniform and as free from grain as possible. This may, forinstance, be effected by rotation and simultaneous warming on a'centrifugal apparatus or the like. i then expose the plate directlythatis, without interposing a from five to fifteen minutes will generally befound sufficient. that the condition which the sensitive coating hasobtained by its exposure to light, what we may call its graduatedhardening, and with it its graduated ermeability to acids andcorresponding etc ing capability in the details, is not impeded ordestroyed by such manipulations as melting on it asphaltdust or the likeor by enameling or other procedures liable to destroy theabove-mentioned properties of the coating after its exposure to light.The plate to be etched, with the copy obtained thereon, is then immersedinto the etching-bath and the etch- ,ing allowed to take place until thewhole' picture appears etcheoheven in the finest details. The strengthor concentration of the etching-bath is that usually employed in jetching processes of this character, and where a bath of chlorid ofiron, (FeCl which gives good results with a plate pre pared as above, isemployed the stren th of the same varies between 30 an .Baum. Accordingto the nature of the subject and of the detail and shading thereof,several etching-baths of different degrees of concentration may beemployed, as will be understood by those skilled in the art. Thetemperature of the etching agent and the selection of the same arematters which are governed largely by the various conditions of the workand are matters of detail which, as well as in general all the differentmanipulations, procedures, and materials used in this process, thoseskilled in the art will readily select.

I find that it is better during the etching process not to brush away orshake .out the deposits formed by the etching agent on the plate, asthey form the best protection against any injury of the finest parts inthe further etching process.

By keeping the sensitized coating in its condition of graduatedhardening, and thereby graduated permeability to acids; as beforementioned, a correspondingly-graduated etching takes place, the variouspoints or stipples in consequence of a partial etching oil of their topslying in different levels, so that in printing the taking of and givingoff the printing-ink will be graduatedly stronger lin the intag lio(plateprinting) process or Care should now be taken v and the like.

etching off of the graduatedly fainter in the relief-printing process. I

After the etching operation is completed as above the plate is removedfrom the etching-bath and cleaned in the usual -manner and is then readyfor printing. The partial printing elements before mentioned socharacteristic for the resent process may be kept, according to t 1epuroses in view, stronger or lighter or even so elicate as not to beseen by the naked eye and only under the microscope, and yet it will beeffective in )rintin The plates etched according to this method may beused for the typographical printingpress relief-printing as well as forplate-printing, intaglio. For plate-printing purposes of course adiapositive has to be employed instead of a negative, as used for thereliefprintin process.

The irect copy of the photographic plate or film onto the plate to beetched in connection with the above-described manner of directly etchininsures the highcstperfection of the reproduction in the various kindsof printing and at the same time renders the reproduction considerablycheaper and more easy to make.

Obviously this process may be employed also for ornamenting surfaces andplates of metal or other material and for making signs inta lio plateshereinbefore To not of the present in- The relief and described as thevention are not are separately covered in my concurrent ap plications,Serial No. 232,761, (No. 5,) and Serial No. 232,762, (No. 6,) filedNovember 14, 1904.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. In the art of producing photomechanical printing-plates, the processwhich consists in exposing a plate provided with a sensitized film underan ordinary continuous negative or diapositive and without the inagentwithout the application of any etching resist to the sensitiz coating.

3. Inthe art of producing photomechan ical printing-plates,. the processwhich consists in exposing plate provided with an or dinary sensitizedcoatin under an ordinary continuous negative or iapositive and withoutthe interposition of a screen, etching said plate, and leaving thedeposits, formed by.

the etching action, on the plateuntilthe end of the etching operation.

4. In the art of producing photomechanical printir'ig-plates, theprocess which consists in exposing a plate provided with a smoothungrained sensitized coating under an ordinary continuous negative ordiapositive and without the interposition of a screen, etching said,plate and leaving the deposit from'the etching agent on the plate.

5. The process of producing photomechanical printing-plates, whichconsists in exposing a plate coated with a layer of bichromatizedgelatin under an ordinary continuous negative without the interpositionof a screen, then immersing such plate into an,

etching-bath without the prior ap, lication of any etching resist andleaving t e deposits from. the etching bath on the plate.

In testimony whereof I aflix my signature in presence of two witnesses.

EMANUEL SPITZER. Witnessesz' HENRY R. MoGINNIs. CLARA. I. PARKER.

